Titanium oxynitride is a compound which is mainly composed of titanium-oxygen-nitrogen and is generally represented by TiNxOy and which is called titanium black. Since titanium oxynitride has blackish color and conductivity, it is added to resins, paints, inks, cosmetics, etc. as a black pigment, and contained in films, fibers, toners, magnetic recording media, etc. as a conductivity-imparting agent. As such a titanium oxynitride, for example, Patent Document 1 discloses a black titanium oxynitride pigment powder containing 4-30% by weight of oxygen and 5-20% by weight of nitrogen (O/N weight ratio: 6-0.2) and having a value L of 14-8 which is obtained by heating titanium dioxide powder at a temperature of 550-950° C. under flowing of ammonia gas.
On the other hand, there is further known titanium nitride mainly composed of titanium-nitrogen and generally represented by TiN as a titanium compound used as a black pigment, and, for example, Patent Document 2 discloses a black titanium nitride powder mainly composed of TiN and containing 1-4% by weight of oxygen and 20-30% by weight of nitrogen, which is obtained by reacting titanium tetrachloride gas and ammonia gas at a temperature of 700-1500° C. to prepare a TiN powder and then oxidizing the surface layer of the powder to titanium oxynitride by flowing a nitrogen-oxygen mixed gas.
Patent Document 1: JP-B-3-51645
Patent Document 2: JP-A-64-37408